A “password” is a method of authenticating a user or system to a server or service. Generally, a password includes a string of characters that is difficult to understand, guess, or reproduce. The harder the string is to understand, guess, or reproduce, the stronger is the password.
Some other types of passwords allow a user to draw a pattern with a finger or a stylus. The drawn pattern itself operates as a password and is compared with a pre-stored pattern. A match within a tolerance allows the user or system to be authenticated, a mismatch rejects the password.
Some other types of passwords allow a user to connect the dots in a dot matrix using a finger or a stylus. The pattern in which the dots are connected operates as a password and is compared with a pre-stored pattern. A match within a tolerance allows the user or system to be authenticated, a mismatch rejects the password.
Biometrics are also commonly used as passwords. For example, a pattern of lines and points in a user's fingerprint is stored as the user's password. More than one such fingerprint patterns may be stored for a user. When the user presents the fingerprint, the pattern in the presented fingerprint is matched within a tolerance with the stored pattern or patterns to authenticate the user.
Hereinafter, a “user” can be a human user or a system, who/which can present a password for authentication. Hereinafter, a “server” is any machine or service that can accept a password from the user and authenticate the user.